SUMMARY Since updating to Kwin 5.24.5, my monitor setup may be misidentified after waking the screen up from energy-saving mode. This causes a whole bunch of issues and requires restarting the session to make it work properly again. STEPS TO REPRODUCE 1. Open a plasma desktop Wayland session with a multi-monitor setup 2. Wait for screens to automatically enter energy saving mode 3. Wake up screen from energy saving mode OBSERVED RESULT Second monitor may be misidentified (In my case, this is either as "California Institute of Technology" or "unknown HDMI-A-1-unknown"). There are several other effects that may appear alongside this, most notably: 1. The panel will be present on the second monitor as if is was primary monitor, despite kscreen still reporting the main monitor being the primary 2. The primary monitor will turn black. Apps can still be dragged onto this monitor, but the desktop appears to no longer be present 3. The second monitor will scale itself up to the scaling used by the primary monitor (causing everything to appear excessively large) 4. The second monitor will lower it's frame rate from 144Hz to 60Hz Any attempts to return the settings to normal while the secondary monitor is misidentified has no effect EXPECTED RESULT Screen layout after waking should be identical to the screen layout before entering energy saving SOFTWARE/OS VERSIONS Linux: 5.17.5-zen KDE Plasma Version: 5.24.5-1 KDE Frameworks Version: 5.93.0-4 Qt Version: 5.15.3 ADDITIONAL INFORMATION I have a very niche monitor setup. The primary monitor is my laptop monitor, which is 2880x1800@90Hz. Due to the high resolution, it is scaled at 150%. The second monitor is 1920x1080@144Hz, and requires no scaling. The second monitor is positioned diagonally above and to the left of the primary monitor. (In a style somewhat reminiscent of the Z tetromino)
Not actually as niche a monitor setup as you might expect. Except for the diagonal positioning part. :)
This is probably a regression caused by https://invent.kde.org/plasma/kwin/-/merge_requests/2203 Need to figure out some workaround for the race condition
*** This bug has been marked as a duplicate of bug 449285 ***